The invention relates to a pedal mechanism having a four-bar parallelogram formed from an upper holding part, a lower holding link with a footplate attached thereto, and two roughly parallel legs.
In order for it to be possible to adapt the operation of pedals, for example in a motor vehicle, to the different size of drivers and thus to the different position of the optimum force introduction point for the driver, a pedal mechanism must be adjustable in the direction of travel (X) and/or in height (Z). Adaptation of the pedals to different proportions and sitting habits of the drivers can thus also be carried out.
Solutions known in the prior art for adjustable pedal mechanisms make possible adjustment of the pedal virtually steplessly along a defined, usually curved path.
The pedal mechanism described in the introduction is known from JP 71 91 773. This mechanism has the disadvantage, however, that the adjustment in the X direction takes place on a circular path which is formed by the radius of the distance from the force introduction point to the main bearing, and that, moreover, the main bearing is fixed in its position by arrangement on a support which is stationary in relation to the body. Adjustment is effected by virtue of the spindle driven by the actuating motor 66 attached to the web pressing on the extended end of the lever, as a result of which the four-bar linkage rotates counterclockwise about the pivot bearing. This leads to the pushrod bearing likewise being pivoted, clockwise, about the pivot bearing. The main bearing is fixed, as the bearing shaft is articulated on the stationary bearing block. A further disadvantage can be seen in the fact that there is no non-positive connection between the threaded rod and the lever end. In this connection, moreover, only an adjustment essentially in the X direction is brought about, so that the points for the pressure point C which can be set by the adjustment lie along a pivoting movement carried out about the main bearing with the radius L2a. The requirement of the automotive industry that the angular position of the pushrod may change by only a very narrowly dimensioned angular range on adjustment cannot be met by this arrangement.
From EP 0 936 527 A2, an adjustable pedal arrangement for motor cars is known, with an auxiliary lever which is mounted pivotably on a front shaft and is moved by a pedal lever which is mounted pivotably on a rear shaft arranged behind and below the front shaft. The auxiliary lever and the pedal lever are connected by an adjustable rod which is arranged essentially parallel to the plane in which the front shaft and the rear shaft lie. The auxiliary lever and the pedal lever form, with the adjustable rod, a parallelogram, that side of which formed by the rod is length-adjustable in order for it to be possible to modify the initial angular position of the footplate which is attached at the lower end of the pedal lever. Connected to the auxiliary lever is an operating rod for a brake or a clutch, which is moved by the forward movement of the footplate. In this way, the auxiliary lever, which moves the operating rod (pushrod), is moved by means of the pedal lever and the adjustable rod. Modification of the setting angle of the footplate makes possible greater variation of the footplate position without having to raise the arrangement in height of the footplate excessively, as the parallelogram arrangement keeps the pedal travel essentially unchanged.
A pedal mechanism described in the introduction is known from U.S. Pat. No. 3,151,499. In this pedal mechanism, the upper holding part, with an integrated pushrod bearing, is pivoted counterclockwise by a spring about the main bearing to come up against a stop fixed to the body. One of the levers, which is articulated by one end on the main bearing, can be pivoted counterclockwise by a length-adjustable spindle which is supported in relation to the body. In this way, the lower holding link, and with it the footplate, is, on a circular path, adjusted backward predominantly in the X direction and at the same time downward slightly in the Z direction. Independent height adjustment of the footplate in the Z direction is not possible with this pedal mechanism.